[Anticonvulsive drug therapy. Historical and current aspects]

The development of new antiepileptic drugs in recent years has enlarged the number of anticonvulsant compounds for the treatment of intractable focal epilepsies. The anticonvulsant potency of these drugs is usually compared by the number of patients who achieve a reduction in seizure frequency of more than 50%. Such an effect can be observed in approximately 20-30% of patients with pharmacoresistant focal epilepsies and is about the same with all the new compounds. In addition to the influence on focal seizures some of the novel anticonvulsant drugs exhibit efficacy in generalized seizures or in Lennox-Gastaut syndrome. In general there are fewer side effects in newly developed drugs than in standard anticonvulsants. However, in some cases characteristic side effects may occur: weight gain, depression or psychosis from vigabatrin; lamotrigine may provoke allergic rashes and felbamate may cause gastrointestinal side effects and sleeplessness. Apart from felbamate, there are no interactions with an antiepileptic comedication or they are of little importance. The development of the new anticonvulsants follows a rational design based on pathophysiological aspects: the main aim is to influence synaptic transmission, resulting in an increase in inhibitory and a decrease in excitatory transmitters. Thus, vigabatrin and tiagabine enhance the endogenous GABA amount, whereas felbamate and remacemide interact with the NMDA-receptor complex. Because it is not possible to draw sufficient conclusions from add-on studies in clinical testing it is necessary to establish new forms of trial design. Monotherapy designs are favored because they lack possible interactions with comedication and make the anticonvulsant efficacy of the compound better comparable to those of established anticonvulsants.(ABSTRACT TRUNCATED AT 250 WORDS)